Polished-rod clamp



E. P. WEISTER.

POLISHED ROD CLAMP.

APPLICATION FILED MAR. 18. 1920.

Patented Nov. 8, 1921.

awvmboz 5M0 WEIJT Z UNITED STATES PATENT OFFICE.

POLISHED-ROD CLAMP.

Application filed March 18, 1920.

To aZZ whom it may concern:

Be it known that I, EDwARD P. .VEISTER, a citizen of the United States, residing at Ranger, in the county of Eastland and State of Texas, have invented certain new and useful Improvements in Polished-Rod Clamps, of which the following is a specification.

The invention relates to clamps and more particularly to polished rod clamps.

In oil and other bored wells it is necessary from time to time to change the length of the string of rods either by lengthening or shortening the same according to the depth of the well or the level of the liquid therein. This is accomplished by adding or removing a section of the rod. During this operation a clamp is attached to the polished rod which reciprocates within a stufiing box. The upper extremity of the polished rod is then disconnected from the walking beam, bull wheel or other actuating mechanism, and the polished rod together with its attached string of rods is drawn upward until one of the joints in the string of rods is above the surface of the well. A foot clamp is then attached to the rod below the one to be removed, if such is the case, or below the joint of the rod attached to the polished rod, if a section of rod is to be inserted, to prevent the string of rods from slipping down into the well. The polished rod is then disconnected from the string of rods and raised further to permit a section to be inserted or lowered if a sect-ion is taken out. The parts are then connected, the foot clamp removed, the string of rods lowered into the well, the polished rod connected to its operating mechanism and the polished rod clamp released. The clamps generally used for this purpose are constructed of cast iron and are attached to the polished rod by two bolts. It has been found that these clamps have a tendency to break and to allow the polished rod together with its attached string of rods to slip down into a well from which it is recovered with great difficulty. Also in this type the operator must have a wrench and both hands are required for the adjustment of the clamping bolts. Moreover, it is difficult to determine when the clamp is set tight enough to support a string of rOd sections.

One of the objects of the invention is to provide a clamp of the type described that Specification of Letters Patent.

Patented Nov. 8, 1921.

Serial No. 367,003.

is quickly and easily attached to a polished rod without the use of tools.

Another object is to provide a clamp that may be easily operated at a distance from the pump.

Another object is to provide a clamp that automatically grasps the polished rod more tightly in proportion to the weight of the string of rods so that its grip is never insufficient for the weight to be sustained and after the same is once set if the rod tends to slip down into the well the clamp sets tighter and stops such slipping.

Another object is to provide a polished rod clamp-that is simple, strong and durable in construction and one that may be manufactured at small cost.

Vith such objects in view, as well as other advantages which may be incident to the use of the improvements, the invention consists in the parts and combinations thereof hereinafter set forth and claimed, with the understandingthat the several necessary elements constituting the same may be varied in proportion and arrangement without departing from the nature and scope of the inventlon.

In order to make the invention more clearly understood there are shown in the accompanying drawings means for carrying the same into practical effect, without limiting the improvements, in their useful applications, to the particular constructions which, for the purpose of explanation, have been made the subject of illustration. In the said drawings:

Figure 1 is a perspective view of the clamp attached to a polished rod and illustrating one manner in which the same may be operated from a distance.

Fig. 2 is a perspective view of the encircling member.

Fig. 3 is a perspective view of the clamping cam member.

Fig. 4 is a perspective view of the detachable pivot.

The clamp consists of a substantially U- shape encircling member 1 having two arms 2 provided with pivot holes 3 and adapted to receive a detachable pivot member 4 having holes 5 to receive retaining cotter pins 6. The member 1 is applied to a vertically reciprocating polished rod 7 operating in an oil pump tubing 8 through a suitable stufling box 9 secured to the top of said tubing. Pivoted on the pin 4 and between the arms 2 of the member 1 is a clamping cam member having an enlarged cam head 10 provided with a pivot hole 11 designed to register with the holes 3 in the member 1 and to receive the detachable pivot member 41. 12 is an operating handle formed with or attached to the head 10. The cam head is formed with an eccentric cam face 13 adapted to engage the polished rod 7 and create a biting or binding action against the member 1. The face 13 is preferably made concave, as by means of a semi-circular groove 14 having preferably a roughened or diagonally serrated surface 15 designed to present a greater and more secure bearing or biting surface 011 the rod 7.

If it is desired to operate the clamp from a distance there is provided a hole 16 in the extremity of the handle 12 in which may be fastened a rope or cable 17 operated on a sheave or'pulley 18 and leading thence to the place from which it may be desired to operate the clamp.

For assembling the clamp with the polished rod the detachable pivot member 4 is removed permitting the cam member 9 to U-shaped member.

be taken out from between the arms 2 of the member 1 (Fig. 2). The member 1 is then slipped around the polished rod and the cam member 9 and pivot 4 replaced as seen in Fig. 1. The clamp may then be ad released and left in position on the rod resting upon the stuffing box allowing the polished rod to reciprocate freely through the "What is claimed is In a rod clamp, a yoke member, a flat oval shaped gripping member eccentrically pivoted between the arms of the yoke memher, said pivot being in the major axis of the gripping member, the end of the gripping member remote from the pivot being serrated, a handle on the gripping member, said gripping member being adapted to grip and hold a rod against movement in either direction through the yoke.

In testimony whereof I affix my signature.

EDWARD P. WEISTER. 

